Paper and process of making the same



Patented Feb. 18, 1930' DOZIER FINLEY, OF BERKELEY, CALIFORNIA, ASSIGNOR TO THE} IPARAFFINE COM- PANIES, INC., 0]? SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELAWARE PAPER AND PROCESS OF MAKING THE SAME No Drawing.

My invention relates to the making of fibrous sheets, such as paper or felt, and particularly to such sheets having the quality of being water-proof.

One of the objects of the invention is the provision of a Water-proof fibrous sheet characterized by low production cost.

Another object of the invention is the provision of a paper and process of making the same in which the Water-proofing material which is much cheaper than the paper stock may be used in quantities far in excess of that considered sound practice under previous methods.

Another object of the invention is the provision of a paper in which a mineral filler may be incorporated with the water-proofing material.

Still another object of the invention is the provision of a paper which is water-proof and at the same time possessed of germicidal qualities.

My invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the invention. It is to be understood that I do not limit myself to the showing made by the said description as I may adopt variant forms of my invention within the scope of the claims.

In general terms the paper of my invention comprises a paper stock to which is added, While the stock is still in the beater, a quantity of'a bituminous emulsion. The emulsion and stock are thoroughly mixed together by the agitators or by the heaters, and passed successively thru the machine mixing box, the screens and onto the wire of a Fourdrinier machine or into the vat of the cylinder machine, as the case may be. My process works well with any kind of paper stock or felt stock, though it is obvious that the emulsions of a dark color will impart a dark color to the product. Under ordinary circumstances a lime-alum-asphalt emulsion of the kind described in my co-pending application Serial No. 61%,280 would be used, though the limesulphuric acid-emulsion described in such copending application, as a variant of my preferred emulsion, may be used equally Well.

Application filed January 17, 1923. Serial No. 613,279.

In the preparation of the emulsion, which is explained at length in my said co-pending application, I slake forty pounds of quicklime with sufficient Water to bring the mass to a plastic condition. The slaked lime is then transferred to a suitable mixer Where it is thoroughly beaten. I then thin out the slaked lime, while still in the mixer, with boiling Water until forty-one gallons of water have been used altogether, including that used in slaking. The lime mixture is set in agitation and at a temperature of about 190 F., and a solution of sixteen pounds of papermakers alum in live gallons of boiling Water is added. This quantit is dependent on the material having in it su stantially seventeen per cent of aluminum oxide. The purpose of the salt is to effect a precipitation from the mixture of insoluble aluminum hydroxide and the nearl insoluble calcium sulphate, and since insu cient alum is added for complete reaction with the lime, an .excess of calcium hydroxide remains in the mixture.

lVhilc continuing the thorough agitation of the mass now in the mixture and maintaining it at substantially the same temperature, previously stated, I slowly add 400 pounds of D-grade California asphalt having a penetration of 50, by the method of the American Society for Testing Materials, standard for 1921, which has previously been brought to a temperature of 190 F., at which it is fluid. After thorough incorporation of the asphalt the resultant product is transferred to suitable containers.

Copper sulphate or blue stone may be used in making this emulsion in exactly the same manner as the aluminum sulphate, but With this exception: copper sulphate solution added to a hot mixture of Water slaked lime and water breaks down into a dark brown or black copper oxide. If, however, the temperature is kept at or about 150 F., the copper hydrate is produced in the normal manner, with only a slight break-down and the making of the emulsion may proceed as in the case of the aluminum sulphate formula.

Sulphuric acid may be used and sulphuric anhydride, and carbonic anhydride may also be used, the latter two in the form of fumes and gas respectively. In the case of these three neutralizing agents, the products of the reaction are the calcium salts of the acid radical and water, which latter reaction product becomes apart of the Water employed in the process. a

. Substances other than asphalt, above specified may be emulsified by the process, and these include petroleum grease or Vaseline, 1O oxidized asphalt, stearin pitches, coal tar and asphalt oils.

If desired, the 400 pounds of asphalt referred to in the process as outlined above, may be replacedby'a mixture of 200 pounds 5 of D-grade asphalt into which has been stirred 200 pounds of crushed limestone which has been screened through a 120 mesh screen. In place of limestone, any one of a large number of powdered or pulverulent materials may be employed. With such a mixture each asphaltic particle incloses one or more particles of the filler material.

The D-grade California asphalt referred to, comprises an asphalt derived from a petroleum of an asphaltic base by the process of distillation, accompanied by the use of steam in the still, the asphalt having a penetration of fifteen to fifty at 77 F., by the method of the American Society for Testing Materials, standard of 1921.

To a quantity of paper stock which has been pulped or beaten in a paper mill beater, there is added while the stock is still in the beater or after it has been run into the chest,

a quantity of the emulsion above described. For each 1,000 pounds of the paper stock, (dry weight), in the beater or chest, I prefer to use about 800 pounds of the emulsion. The mixture of stock and emulsion is then 40 thoroughly agitated and passed thru the machine mixing box, the screens and then onto the wire of a Fourdrinier machine or into the vats of the cylinder machine, as the case may be.

,normally are cut .with slots approximately .020 inches wide and the stock for the machine must pass thru these slots, it is preferred to mix the emulsion with water before it is added to the stock and to screen it thru a similar screen. The particles which are too large to pass this screen may be returned to the emulsion making process and there made over into new emulsion. Deduction should, of course, be made for the amount withdrawn so that the proper net amount of emulsified bituminous material is added to the paper stock, as above explained.

While the above named proportions give satisfactory results, it is possible to use 2,000

pounds of emulsion to 1,000 pounds of paper stock. On the other hand, it is possible. to reduce the emulsion almost to the Vanishing point, but it-is evident that the water proof qualities will suffer with a decrease in the percentage of emulsion to a low figure. Be-

As the screens of a paper machine ing cheaper, pound per pound of solid, than most paper stock, it' is economy to use as much of the emulsion as possible. This is in contrast to the use of rosin size, which is, pound per pound of solid, more expensive than the usual run of paper stock. If the softening point of the asphalt is too low, that is, if it is a so-called liquid asphalt, it is found to be adhesive and causes sticking of the paper or felt to the press rolls of the machine. Any kind of paper stock or felt stock may be used in my process. Since, on a cylinder machine, it is possible to make the completed sheet of paper or board or felt in several layers, according to the number of cylinders on the machine, the stock carrying the water-proofing emulsion may be led to any one or more of the vats of a multi-cylinder machine, thus the completed sheet may be water-proofed thruout, or a water-proof layer may be incorporated in the sheet, or the surface layer, or layers only may be water-proofed, according to the use for which the sheet is intended.

Because the emulsion may be made with comminuted materials inclosed within the asphalt particles, it becomes possible to -heavily load the sheets of paper or felt or board with comparatively low-priced fillers, and this is an especially valuable feature because of the price limitation frequently placed on the production of the sheets.

Another very valuable modification ofthe process is effected by the incorporation, with the emulsion, of a germicidal material, such as the copper-hydrate referred to in the fore. going description of the emulsion, or when tar containing creosote oil-is used in the emulsion instead of the asphalt. Thus a sheet highly resistant to decay and the development of bacterial or fungoid growths mziy be produced.

n the claims I shall use the term paper in its broad significance to include any fibrous sheet, such as ordinary paper, and the various kinds of paper boards and felts.

I claim :v

1. The process of making paper which comprises incorporating into the pulped stock a lime-alum-asphalt emulsion and forming the mixture into a sheet.

2. The process of making paper which comprises incorporating in the pulp a limebitumen emulsion and forming the mixture into a.

sheet.

3.'The process of making paper which comprises incorporating in the pulp a limebitumen emulsion containing a filler, and forming the mixture into a sheet.

4. A paper comprising a fibrous sheet containing lime and bitumen derived from an emulsion of said materials.

5. A waterproof paper made from a fibrous sheet containing pulverulent material in acarrier of emulsified bituminous material, the pulverulent material replacing a. portion of bituminous material ordinarily used for waterproofing pur oses.

6. A paper made from a brous sheet containing pulverulent material in a carrier of emulsified bituminous material.

7. A waterproof sheet made from a fibrous sheet containing particles of bituminous material which have coalesced to entrain a previously carried filler and a residual emulsifying agent.

8. A waterproof paper comprising a fibrous sheet havin thoroughly incorporated therein an emulsi ying agent and bitumen derived from an emulsion of said materials, and a pulverulent filler.

9. A waterproof paper comprising a fibrous sheet having thoroughly incorporated therein an emulsifying agent and bitumen derived from an emulsion of said materials, and a pulverulent filler, the pulverulent filler replacing a portion of the bituminous material ordinarily used for waterproofing purposes.

10. A waterproof paper comprising a fibrous sheet containing lime and bitumen derived from an emulsion of said materials, and'a filler.

In testimony whereof, I have hereunto set my hand.

DOZIER FINLEY. 

